Centrifuge having a lubricant system

ABSTRACT

Disclosed is a centrifuge including a rotatable centrifugal drum and a drive spindle to drive the centrifugal drum. The drive spindle is rotatably mounted via a bearing in a housing supported elastically on a machine framework. Further included is a drive device including a drive motor to rotate the drive spindle and a lubricant system to lubricate the bearing. The lubricant system is configured to deliver lubricant from a lubricant supply tank through a lubricant channel into a region of the bearing. An injection device is arranged downstream of the lubricant-supply tank and is configured to deliver the lubricant into the region of the bearing by dispensing quantities of lubricant in temporally discrete pulses with a limited-time air stream. A method is disclosed of directing lubricant into a region of a bearing of the centrifuge as noted above.

This application is a divisional of U.S. patent application Ser. No.13/321,643, filed Nov. 21, 2011, which is a national stage ofInternational Application PCT/EP2010/057448, filed May 28, 2010, andclaims benefit of and priority to German Patent Application No. 10 2009022 972.8, filed May 28, 2009, the content of which Applications areincorporated by reference herein.

BACKGROUND AND SUMMARY

The present disclosure relates to a centrifuge, or a separator, with avertical axis of rotation. The centrifuge includes a rotatablecentrifugal drum and a drive spindle to drive the centrifugal drum. Thedrive spindle is rotatably mounted via a bearing in a housing supportedelastically on a machine framework. Further included is a drive deviceincluding a drive motor to rotate the drive spindle and a lubricantsystem to lubricate the bearing. The lubricant system is configured todeliver lubricant from a lubricant supply tank through a lubricantchannel into a region of the bearing.

Such centrifuges, in particular separators, which are suitable inparticular for industrial use in continuous operation, are known fromthe prior art. The known systems include designs in which the drum, thedrive spindle and the electric drive motor are connected rigidly to forma structural unit which then, as a whole, is supported elastically on amachine framework. Examples of such prior art are disclosed in FR1,287,551, DE B 1 057 979 and DE 43 14 440 C1.

Additional technical background is provided by DE 44 08 182, whichdiscloses a belt drive for a separator, and EP 0 756 897 and WO98/57752.

DE 2005 001 539 U1 discloses a separator which has a drive belt and alsohas a circuit-like lubrication system, which is intended for lubricatingthe spindle-bearing means. The separator has a tubular, scraper-likedevice which is intended for pumping out lubricant. Such lubricant,which exits out of the bearing means of the drive spindle of theseparator drive, can be pumped, via a reprocessing unit, into alubricant sump, in which the drive, spindle, designed as a hollowspindle, is immersed by way of its lower end. This arrangement, however,is still relatively long in the axial direction.

WO 2007/125066 A1 discloses a separator with a direct drive, The directdrive device has an electric drive motor with a stator and a motorrotor, which is aligned with the drive spindle, wherein the stator isconnected rigidly to the machine framework and the motor rotor, thedrive spindle, the centrifugal drum and the housing form a unit which issupported elastically on the machine framework and oscillates duringoperation. The bearing device here is arranged between the motor and thedrum. The lubrication means of the bearing devices can be accommodatedabove a partition wall above the drive motor.

Against this background, the present disclosure relates to a furtherimprovement of the construction and the arrangement of the lubricationsystem of centrifuges, in particular separators with a vertical axis ofrotation.

The present disclosure thus relates to a centrifuge that includes arotatable centrifugal drum and a drive spindle to drive the centrifugaldrum. The drive spindle is rotatably mounted via a bearing in a housingsupported elastically on a machine framework. Further included is adrive device including a drive motor to rotate the drive spindle and alubricant system to lubricate the bearing. The lubricant system isconfigured to deliver lubricant from a lubricant supply tank through alubricant channel into a region of the bearing. Also included is aninjection device, arranged downstream of the lubricant-supply tank, andconfigured to deliver the lubricant into the region of the bearing bydispensing quantities of lubricant in temporally discrete pulses with alimited-time air stream.

Accordingly, at least one injection device, which is arranged downstreamof the lubricant-supply tank, is provided for the purpose of deliveringthe lubricant. This device is designed for dispensing quantities, forexample, small quantities of lubricant in temporally discrete pulses,with a limited-time air stream, into the region of the bearing. Thismakes it possible for the lubricant requirement to be vastly reduced,for example, when the pulse of oil is blown as a mist into the region ofthe bearing.

The injection device may be designed as an injection lubricator. Suchinjection lubricators may have a piston. According to an embodiment ofthe present disclosure, small quantities of lubricant are therebydispensed in the separator, at intervals, into the bearing region, forexample, at less than 100 mm³ per pulse.

The use of injection lubricators in the field of lubricating a bearingfor a centrifuge has not been considered up until now. However, contraryto original expectation, it has been found that it is possible, usingsuch an injection lubricator, for even a separator intended forindustrial use to be lubricated adequately with only a very small amountof lubricant without continuous operation being adversely affected.

Using an injection lubricator thus makes it possible for the consumptionof lubricant to be reduced to an extremely small quantity, for example,to less than 30 liters per year of operation occurring, for example,over 8000 hours.

It is within the scope of the present disclosure for the injectionlubricator to be designed to dispense a quantity of lubricant by amicropump for up to two seconds long, for example, such that, betweenthe individual pulses, there is a pause of more than 60 seconds, andthat each pulse is up to two seconds long, for example, one second long.

The injection lubricator may be advantageously designed in order todispense a quantity of lubricant by a piston for, up to two seconds longper pulse, wherein the injection lubricator, furthermore, may be setsuch that, between the individual pulses, there is a pause of more than60 seconds, for example, 60 seconds to 180 seconds.

According to the present disclosure, the injection lubricator, mayadvantageously be designed in order to dispense a quantity of lubricantof between 5 mm³ and 100 mm³, for example, between 10 mm³ and 40 mm³, bya piston, for example, every 60 seconds to 180 seconds.

A lubricant supply which uses up only a particularly small amount oflubricant is realized with only a small number of components. Thedesign, according to the present disclosure, is suitable both fordriving via a belt drive and for various types of direct drive with adrive motor arranged in axial extension of the drive spindle or on thedrive spindle. These arrangements also make it possible, according tothe present disclosure, to realize a construction for the drive devicewhich is short in the vertical direction.

It should be noted that the centrifuge, according to the presentdisclosure, may also be designed as a solid-bowl centrifuge.

If the centrifuge is designed as a solid-bowl centrifuge, which may havebearings, for example, on either side of a rotatable drum, and, forexample, at least one such bearing, each mounted in a ring-like housing,it may be advantageous, according to the present disclosure, iflubricant can be delivered, by at least one injection device, out of thelubricant-supply tank into the region of one or both of the bearings.

Also provided, according to the present disclosure, is a method fordirecting lubricant into the region of at least one bearing of acentrifuge, according to the present disclosure, in an advantageous andlubricant-saving manner. A respective oil/air mixture is injected inpulses, by at least one injection lubricator, into the region of the atleast one bearing.

Additional disclosure, according to the present disclosure, is providedin the claims.

Since the spindle may not used for the lubricant circuit, the spindlecan be used for other tasks such as product feeding, for example,through a hollow spindle, according to the present disclosure.

Other aspects of the present disclosure will become apparent from thefollowing descriptions when considered in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION THE DRAWINGS

FIGS. 1 to 3 show partial sectional views of schematically illustrateddrives for separators, or solid-bowl centrifuges, according to thepresent disclosure.

FIGS. 4 a and b show sectional views of bearing regions of a solid-bowlcentrifuge, according to the present disclosure.

FIG. 5 shows a schematic, partial sectional view of a solid-bowlcentrifuge, according to the present disclosure.

DETAILED DESCRIPTION

FIG. 1 shows a sub-region of a separator 1 having a centrifugal drum 2(see FIG. 3) with a vertical axis of rotation D and a supply line (notshown) for material which is to be centrifuged.

The centrifugal drum 2 is positioned on a drive spindle 3. A shroud anda solids trap are not shown.

As shown in FIG. 1, the drive spindle 3 is driven via a drive belt 4,which wraps around a belt pulley 11, which is in one or more parts andis positioned on the drive spindle 3. A driveshaft and a drive motor arenot shown in FIG. 1.

The drive spindle 3 is mounted in a rotatable manner in a housing 7 byway of a bearing, for example, a neck bearing 5, or upper bearing, and afoot bearing 6, or lower bearing. By way of example, the neck bearing 5and the foot bearing 6 have a single rolling-contact bearing. Otherconfigurations, for example with two neck bearings or foot bearings arewithin the scope of the present disclosure but not shown.

The housing 7 is supported by one or more elastic elements 8, 9, forexample, by cylindrical bearings and/or ultra bushings or equivalentbearings, on a machine-framework portion 10. Machine framework portion10 may be designed as part of a primary machine framework or may befastened on a ceiling of a building or the like, according to thepresent disclosure.

The illustration of the housing 7, for example, having, a flange is tobe understood to he an example. The critical factor is for the housing 7to be supported elastically on the machine framework 10 duringoperation, it being designed to be rotationally fixed during operation.It accommodates the bearings 5, 6, in which the drive spindle 3 rotates.

For the purpose of supplying the bearings of the drive spindle withlubricant, use is made of a lubricant system which has alubricant-supply tank 12 and at least one injection device 13, which ispositioned downstream of the lubricant-supply tank 12 and is intendedfor dispensing quantities, for example, small quantities of lubricant intemporally discrete pukes with a limited-time air stream. Accordingly,rather than a permanent air stream, use is made of an airstream pulse,to which the quantity of lubricant is fed.

Also provided are a lubricant-feed line 14, which is arranged downstreamof the injection device 13 and is for directing lubricant from theinjection device 13 into the region of the bearings, for example, thebearings 5, 6, and a lubricant-intercepting tank 15 for interceptingquantities of residual oil dripping off from the region of the bearings.

The feed line 14, which is positioned downstream of the injection device13, may be designed as a pressurized oil line, according to the presentdisclosure.

The lubricant-feed 14 may extend into the region of the neck bearing 5,for example, into the region above the neck bearing 5.

It is within the scope of the present disclosure, that just oneinjection device is provided. However, it is within the scope of thepresent disclosure for one or more injection devices to supplyindividual bearing locations, or all of the bearing locations providedindividually. For such a purpose, it is then expedient to route arespective lubricant-feed line 14 to each of these bearing locations andpossibly a corresponding discharge line (not shown) from each of theselocations. It is within the scope of the present disclosure, also foreach bearing location or each of the bearings to be fed advantageouslyan individually optimized quantity of lubricant.

The line 14 passes through a bore 16 in a housing part 17 connected tothe housing 7.

Lubricant exiting from an open end of the bore thus may spray in amist-like manner from above into the bearing, or bearing 5, 6, of thedrive spindle 3.

As suggested in FIG. 1, the lubricant flows in the first instancethrough the neck hearing 5, from there through a discharge channel 18,for example, an annular chamber on the outer circumference of the drivespindle 3, into and through the foot hearing 6 and then through adischarge channel 19 in the belt pulley 11. How may continue throughfurther elements not shown.

The belt pulley 11 may be in the form of a cup which is closed at thebottom. In the base region, it is connected in a rotationally fixedmanner to the drive spindle 3. The drive belt 4 is positioned around itsouter lateral surface. The belt pulley 11 is closed in the downwarddirection apart from the discharge channel 19, such that all thelubricant exiting vertically downwards from the bearings 5, 6 isdirected outward, through the discharge channel 19, out of the beltpulley 11 or the belt-pulley arrangement.

A lower end of the belt pulley 11 or of the further elements noted aboveprojects into the lubricant-intercepting tank 15, and thereforelubricant 20 dripping off from the drive region is intercepted, andcollected, in the lubricant-intercepting tank 15.

The injection device 13 used may be an injection lubricator for thepurpose of metering small quantities of lubricant.

The used oil collects in the lubricant-intercepting tank 15.

Thus, according to the present disclosure, a residual quantity oflubricant has to be disposed of during operation only extremely rarely.

As shown in FIG. 2, a lower, free end of the drive spindle 3 is immersedin a tube portion 21 in the lubricant-intercepting tank 15. This tubeportion 21 is open in the upward and downward directions and passingthrough the tank vertically. Therefore, it is within the scope of thepresent disclosure for the drive spindle 3 to be a hollow spindle inorder for product to be directed through it into the centrifugal drum 2(not shown).

As shown in FIG. 3, the drive provided for the separator, may be adirect drive. In such a case, an electric drive motor 22 is aligneddirectly with the drive spindle 3.

As shown in FIG. 3, for example, the motor rotor 23 is arranged directlyon the drive spindle 3 and the stator 24 of the drive motor 22 isarranged on the non-rotating machine framework 10.

The bearings 5, 6 and the lubricant system correspond in respect of theoperation of directing the lubricant into the region of the bearings 5,6, to the construction as shown in FIGS. 1 and 2.

The lubricant exiting from the foot bearing 6 is directed away through adischarge channel 25, which passes through the housing 7. The dischargechannel 25 is aligned with a line 26 which, in turn, opens out into thelubricant-intercepting tank 15, which is integrated in the machineframework 10, The lubricant-intercepting tank 15 is formed to the sideof the drive motor 22. The tank 15 may also enclose the same in themanner of an annular tank. The line 26 may he of flexible design, toallow it to move along with the housing 7.

The region between the drive spindle 3 and the housing 7 may be sealed,for example, by a glide ring seal 27, in order to prevent lubricant frombeing able to drip into the region of the drive motor 22. As analternative, it is within the scope of the present disclosure to sealthe region between the drive spindle 3 and the intercepting chamber orlubricant-intercepting tank 15.

The lubricant-intercepting tanks 15 may be provided with a closableoutlet opening, in order for it to be possible to let out possibly oldlubricant residues.

It is within the scope of the present disclosure for thelubricant-supply tank 12 and/or lubricant-intercepting tank 15 to beintegrated at various locations in the machine framework 10 or forseparate tanks to be arranged for their respective purposes on themachine framework 10.

Whereas the discharge channel 25, as shown in FIG. 3, is arrangedbeneath the foot bearing 6, it within the scope of the presentdisclosure for it to be arranged between the foot bearing 6 and the neckbearing 5. The embodiment shown may be preferred since it provides forall the lubricant residues to be directed away out of the bearing regionto good effect.

The centrifuge according to the present disclosure may be designed as asolid-bowl centrifuge.

FIG. 5 shows a solid-bowl centrifuge, or decanter, having a rotatabledrum 101 with, for example, a horizontal axis of rotation H. Also shownis a rotatable screw 102, arranged within the drum 101, and with a drivemotor 103 for rotating the drum 101 and the screw 102.

The drum 101 of FIG. 5 is arranged between a drum bearing 104, on thedrive side, and a drum bearing 105, remote from the drive side. The drum101 is rotated in a rotatable manner, by way of drum bearings 104, 105,on a machine framework/base 106.

For driving purposes, drive motor 103 uses belt drives 107, 108 to drivetransmission input shafts 109, 110, corresponding to the one or moredrive spindles, by which the screw 102 and the drum 101 are rotated viaone or more transmission arrangements 111. Other drive arrangements arewithin the scope of the present disclosure. A product inflow andcorresponding outflows for at least one liquid phase and a solid phaseare not shown. These elements, however, are known to a person skilled inthe art.

The lubricant system for lubricating the bearings 104, 105 is arrangedon the machine framework 106 in a manner similar to FIG. 1 but not shownhere. The system is designed in order to deliver lubricant out of alubricant-supply tank. The lubricant-supply tank may be integrated inthe machine framework 106. The system has at least one injection device,which is arranged downstream of the lubricant-supply tank and isdesigned for dispensing quantities, for example, small quantities oflubricant in temporally discrete pulses, with a limited-time air stream,into the region of the bearings 104, 105.

The at least one injection device has positioned downstream of it alubricant feed line 114, shown as an arrow, which has a bore 115 in ahousing 112 of the bearings 104, 105 (see FIGS. 4 b and 5), and by whichbore 115 the lubricant can be delivered into the region of one or bothof the bearings 104, 105. That delivery may be above the bearings 104,105 or to the side of the hearings 104, 105 on the horizontal spindle.

Just one injection device may be provided. However, it is within thescope of the present disclosure for one or more injection devices to beprovided and for them to supply individual bearing locations, or all ofthe bearing locations 104, 105 individually. It may be expedient toroute a respective lubricant-feed line 114 to each of these bearinglocations 104, 105 and possibly a corresponding discharge line (notshown) from each of these locations. It is within the scope of thepresent location for each bearing location 104, 105 or each of thebearings 104, 105 to be fed, advantageously, an individually optimizedquantity of lubricant.

According to the present disclosure, lubricant may be injected in amist-like manner from above into the bearings 104, 105.

The lubricant thus flows through the respective bearings 104, 105 tovertically lower regions of the bearings 104, 105 and from there,through at least one discharge channel, or two discharge channels 118 a,118 b, beneath and what may also be on one side, or on either side, ofthe respective rolling-contact bearings 104, 105, into alubricant-intercepting tank 120 (see. FIG. 4 b) beneath the respectivebearings 104, 105, and may be integrated in the machine framework 106.

As described herein in relation to the separator, oil is injected intoan air stream through the bore 115. In embodiments of the presentdisclosure, the bore 115 may have a constriction, and therefore, forexample, upstream of the exit, a nozzle is formed. The nozzle has adiameter which is smaller than that of the bore 115, for example, by 0.1to 0.5 mm.

It may be advantageous, according to the present disclosure, for thebores 115 to have a diameter of 0.3 mm to 5 min, The a diameter may be0.5 mm to 1.2 mm, or, for example, 0.8 to 1.2 mm, in order reliably tofeed 1-100 mm³ per pulse, or, for example, 3-20 mm³ per pulse, oflubricant.

In accordance with the present disclosure, more than 10 seconds, or, forexample, more than 60 seconds, may elapse between the pulses.

It is within the scope of the present disclosure to have shaft-sealingrings 112 on either side of the bearings 104, 105, in order to seal therespective rolling-contact-bearing chamber 113, through which the oilcan flow. The sealing rings 112 may be designed as a shaft-sealing ringor as a lamellar sealing device or, for example, as a double-action sealand/or as a contact seal. Glide ring seals are within the scope of thepresent disclosure, if a high level of sealing is to be provided.

An optional guide ring 119 between the respective bearings 104, 105 andsealing devices may optimize the operation of the lubricant beingdirected away into the discharge channel or channels 118 a, b.

Although the present disclosure has been described and illustrated indetail, it is to be clearly understood that this is done by way ofillustration and example only and is not to be taken by way oflimitation. The scope of the present disclosure is to be limited only bythe terms of the appended claims.

What is claimed is:
 1. A centrifuge, comprising: a rotatable centrifugaldrum; a drive spindle to drive the centrifugal drum, which drive spindleis rotatably mounted via a bearing in a housing supported elastically ona machine framework; a drive device including a drive motor to rotatethe drive spindle; a lubricant system to lubricate the bearing, thelubricant system configured to deliver lubricant from a lubricant-supplytank through a lubricant channel into a region of the bearing; and aninjection device, arranged downstream of the lubricant-supply tank, isconfigured to deliver the lubricant into the region of the bearing bydispensing quantities of lubricant in temporally discrete pulses with alimited-time air stream; wherein the bearing includes a neck bearing anda foot bearing and the lubricant is delivered into a region of the neckbearing or into a region above the neck bearing; wherein the drive motoris aligned with the drive spindle and is configured to rotate the drivespindle directly.
 2. A centrifuge, comprising: a rotatable centrifugaldrum; a drive spindle to drive the centrifugal drum, which drive spindleis rotatably mounted via a bearing in a housing supported elastically ona machine framework; a drive device including a drive motor to rotatethe drive spindle; a lubricant system to lubricate the bearing, thelubricant system configured to deliver lubricant from a lubricant-supplytank through a lubricant channel into a region of the bearing; and aninjection device, arranged downstream of the lubricant-supply tank, isconfigured to deliver the lubricant into the region of the bearing bydispensing quantities of lubricant in temporally discrete pulses with alimited-time air stream; wherein the region of the bearing is configuredsuch that lubricant flows through the bearing, and that the lubricant isthen directed away through a discharge line out of the region of thebearing and into a lubricant-intercepting tank; and wherein the drivespindle is arranged such that a free end of the drive spindle is guidedthrough the lubricant-intercepting tank.
 3. A centrifuge, comprising: arotatable centrifugal drum; a drive spindle to drive the centrifugaldrum; a drive device including a drive motor to rotate the drivespindle; a lubricant system, the lubricant system configured to deliverlubricant from a lubricant-supply tank; and an injection device,arranged downstream of the lubricant-supply tank, is configured todeliver the lubricant by dispensing quantities of lubricant intemporally discrete pulses with a limited-time air stream; wherein thecentrifuge is a solid-bowl centrifuge including a bearing on either sideof the rotatable drum, the bearing being arranged in a ring-shapedhousing, and further wherein. lubricant is delivered by the injectiondevice from the lubricant-supply tank into a region of the bearing. 4.The centrifuge as claimed in claim 3, wherein an axis of rotation of thedrum is oriented horizontally, and the housing has a bore through whichthe lubricant is delivered into the region of the bearing either abovethe bearing or to a side of the bearing on the spindle that is orientedhorizontally.
 5. The centrifuge as claimed in claim 3, further includinga discharge channel which opens out into a lubricant-intercepting tank.The centrifuge as claimed in claim 4, wherein the bore includes anozzle.
 7. The centrifuge as claimed in claim 3, wherein a sealingdevice is provided on either side of the bearing.
 8. The centrifuge asclaimed in claim 5, wherein the discharge channel opens out directly orvia another discharge channel into the lubricant-intercepting tank. 9.The centrifuge as claimed in claim 5, further comprising an additionaldischarge channel.